What does Kepler's third law imply about planetary motion?
A)All planets orbit the Sun at the same speed.
B)Planets closer to the Sun orbit at a slower speed than planets further from the Sun.
C)Planets further from the Sun orbit at a slower speed than planets closer to the Sun.
D)Planets further from the Sun orbit at a faster speed than planets closer to the Sun.
E)This law implies nothing about a planet's motion.

Question

Quizplus · Accepted Answer

Kepler's third law states that the square of a planet's orbital period is proportional to the cube of its average distance from the Sun. This implies that planets further from the Sun have a longer orbital period, meaning they travel at a slower speed, while planets closer to the Sun have a shorter orbital period, meaning they travel at a faster speed. Kepler's third law states that the square of a planet's orbital period is proportional to the cube of its average distance from the Sun. This implies that planets further from the Sun (larger average distance) have longer orbital periods, and therefore they must move at a slower speed to complete their orbit in the same amount of time as planets closer to the Sun (smaller average distance).

What Does Kepler's Third Law Imply About Planetary Motion